Electric-arc lamp



2 Sheets-Sheet 1.

(No Model.)

0. C. STIRLING. ELECTRIC ARC LAMP.

Patented Nov. 16,1897.

a a? a 9 y w fir y y n. J/ n Em i LE EEEEE (No Model.) 2 Sheets-Sheet 2.

U. G. STIRLING. ELECTRIC ARC LAMP.

No. 593,697. Patented NovLlG, 1897.

Nil-ED Stars arnnr Orrrcn.

CLARENCE C. STIRLING, OF HARTFORD, CONNECTICUT, ASSIGNOR TO EDMUNDHUDSON, OF TEMPLETON, MASSACHUSETTS.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 593,697, dated November16, 1897. Application filed February 6, 1897. Serial No. 622,264 (Nomodel.)

To aZZ whom it may concern.-

Be it known that I, CLARENCE O. STIRLING, of Hartford, county ofHartford, State of Connecticut, have invented an Improvement inElectric-Arc Lamps, of which the following description, in connectionwith the accompanying drawings, is a specification, like letters andfigures on the drawings representing like parts.

This invention relates to electric-arc lamps of that class in which therays of light therefrom are reflected upwardly and in which the arc ismaintained in a fixed or predetermined position.

The invention has for its objects, first, to improve the construction ofthe carbon-feeding mechanism, whereby the carbons are antomatically fedtoward each other to maintain the arc in a fixed or predeterminedposition 5 second, to provide an improved form or construction ofactuator for said carbon-feeding mechanism, and, third, to improvecertain details in the general construction of the lamp.

The invention consists in embodying in an arc-lamp certain feedingmechanism for the carbons, comprising ahollow shaft and a rod whichenters and moves telescopically therein, said hollow shaft beingexternally screwthreaded and receiving upon it the lower carbon support,which rises and falls as said hollow screw-shaft is turned in one or theother direction, and said hollow screw-shaft being also internallyscrew-threaded and receiving within it the aforesaid rod, which isexternally screw-threaded, and as said hollow screw-shaft is turned saidrod will be moved up and down according to the direction of movement ofsaid hollow screw-shaft, and the screw-threads are so arranged that assaid hollow screw-shaft is turned in one direction the lower-carbonsupport thereon will be raised and the screw-threaded rod will belowered, and vice versa, and said rod is connected with the upper-carbonsupport, and consequently said upper-carbon support will move with saidrod. The pitch of the screw-threads vary, so that the carbons will movetoward each other at different rates of speed, which is proportioned tothe consumption of the respective carbons, so that the arc can bemaintained in a fixed or predetermined position.

The invention also consists in an actuator for the carbon-feedingmechanism consisting of a motor, comprising a field-magnet which isincluded in circuit in series with the carbons, and a rotary armaturewhich is included in a normally open branch circuit, and acircuit-closer or switch is provided for said branch circuit, which isoperated by a device controlled by the field-magnet of the motor, whichdevice is responsive to variations produced by the varying resistance ofthe arc-as, for instance, a supplemental armature may be providedfor'said field-magnet which is connected with said switch orcircuit-closer, and said supplemental armature has a retractor which isovercome by the attractive force of the field-magnet when but littleresistance is produced by the are, but when said resistance is increasedto a considerable extent said retractor will overcome the attractiveforce of said field-magnet, re-

tracting the armature, and thereby causing the switch or circuit-closerto close said normally open branch circuit.

The rotary armature of the motor is connected with the carbon-feedingmechanism, and when the switch or circuit-closer of the branch circuitis open said rotary armature Will remain at rest, but when said switchor circuit-closer is operated and the branch circuit closed said rotaryarmature will revolve and operate the carbon-feeding mechanism.

Figure 1 is a side elevation of an electricarc lamp embodying thisinvention. Fig. 2 is a front elevation of the same, parts thereof beingbroken away for clearness. Figs. 3 and 4 are details to be referred to,and Fig. 5 is a diagram of the electric circuit as arranged'in myimproved arc-lamp.

A and B represent, respectively, the lower and the upper carbons. Thelower carbon is placed in a socket formed in a holder a and securelyheld in place by means of a thumb-screw a. The holder a is formed with ashank a which projects down through a bushing a and a spiral spring aencircles said shank a the lower end of which rests upon a shoulderformed in the bushing and the upper end bears against said holder, andthe action of said spring is to thrust the lower carbonholder an upward.The bushing a is mounted in a similar bushing a of insulating materialwhich is fixed in the center of a disk Z). The disk Z) is mounted toslide vertically upon a guide post or bar 0, and is formed with adepending sleeve Z), which embraces said post 0 and is insulatedtherefrom by means of a lining b of anysuitable insulatingmaterial.

The disk Z) is also formed with a depending boss Z), which is internallyscrew-threaded to engage the externally-screw-threaded shaft (Z, whichlatter is revolved in the manner and by the means to be hereinafterdescribed, and acts as a feeding serew to move vertically the disk Z)and lower carbon carried thereby. The post 0 is fixed at its lowerextremity in a base 0, in which base is also journaled the lowerextremity of the feeding or screw shaft (Z. The screw-shaft (Z hasmounted loosely thereon at or near its lower end aworm-gear 0, uponwhich is mounted a pawl (Z that e11- gages a ratchet-wheel (Z fixed tosaid screwshaft (Z, and said worm-gear c is engaged by a worm f, fixedto a shaft 1), which is herein shown as the shaft of the rotaryarmatureof an electric motor. The shaft D is caused to rotate at certain times,as will be hereinafter described, and through the medium of said worm fand worm-gear c the screw-shaft (Z will be rotated in a direction tofeed the disk Z) and parts borne by it upward a short (listanee anduntil said shaft D ceases to revolve.

The upper carbon B is placed in a holderg and is secured therein bymeans of a thumbscrew g. The holder 9 is formed upon or secured to across-piece to one end of which is secured a depending guide-rod g andthe post 0 is made hollow to receive within it said guide-rod whichslides up and down telescopically. The upper end of said cross-piece hassecured to it one end of a threaded rod g", the threads formed thereonhaving one half the pitch of the threads formed upon the exterior of thescrew shaft (Z. The screwshaft (Z is made hollow and interiorlyscrewthreaded to receive within it said threaded rod 9, which is movedup and down by the turning of said hollow screw-shaft (Z. It will thusbe seen that when the screw-shaft (Z is rotated, either by the rotationof the shaft D or otherwise, the upper carbon B will be fed downward athalf the rate of speed at which the lower carbon is fed upward, whichrelation is in proportion to the consumption of the respective carbonsand results in maintaining the are in a fixed position.

A short shaft Zl is-journaled in the base 0, which has fixed thereon apinion h, that meshes with a pinion 7L2, fixed to the screwshaft (Z, andsaid short shaft 71. projects down through the base 0, and its lowerprojecting end is squared to receive a wrench or other implement bymeans of which to revolve the shaft (Z by hand, and so facilitate theadjustment or replenishing of the carbons A andB.

The supporting-rods 1' t" are secured at their lower ends to a disk ofwood or other suitable non-conducting material, and said. disk ishollowed out upon its upper face to receive the base 0. The upperextremities of the supportingrods i '2' are united by a crosspiece 2, ofwood or other non-conductingniaterial, and to said cross piece an eye1'' is secured by means of which the lamp may be suspended.

Upon the disk Z) is mounted an are forming or striking magnetj,thearmature y" of which is attached to a lever f pivoted at one end to apost or upright support j, the free end of said lever being forked anddisposed to rest upon the holder Ct. Circuit contact-sprin Z 7;- aresecured to a block 7" of insulating material sccured to the disk Z).

the arc-forming magnet] and their free ends straddle and slide alongupon the rod 1 To the upper end of the rod 1? one wire of the maincircuit is attached, the other wire of said circuit being attached tothe upper end of the rod '1 To the lower end of the shank a of thecarbonholder is attached a wire 7.1 which connects with the coils of thearc-forming mag net 7'.

The spring (1. tends to hold the lower carbon up against and in contactwiththe upper carbon until the arc-forming magnet is energized, when itsarmature will be drawn downward, carrying with it the lower carbon andmoving said lower carbon a distance sufficient to produce and establishthe arc properly between the two carbons.

The motor which serves as the actuator for the feeding mechanismcomprises a fieldmagnet G and a rotary armature 1'), and saidfield-magnet Gis included in the main circuit, in series with thecarbons, and the rotary armature is included in a branch eir' cuit, andsaid rotary armature is secured to or mounted upon the shaft D, to whichthe worm is secured. Z are the two members of a circuit-closer which isprovided for said branch circuit containing the rotary armature andwhich normally holds open the branch circuit and when operated closesit, and when said branch circuit is open said rotary armature is at restbut when said branch circuit is closed said rotary armature revolves.

It is desired to operate the circuit-closer by a device responsive tovariations in the cui= rent produced by changes in the resistance of thearc, and as a device of this character I provide the field-magnet G ofthe motor with a supplemental armature Z, which is pivoted. at 50, andwhich is connected by a link 51.wit-h one of the members of saidcircult-closer. The field-magnet G is included in the main circuit inseries with the carbons, and the coils of said iield-nmgnet areconnected by means of a wire Z- with a bracket 'm, which is in contactwith the base 0. The wire Z' is also connected with the commutatorbrusha of the motor. The opposite end of the coil of the lield nagnet G isconnected by a wire Z to a binding-post 0, which sup- Thecontact-springs 7. are connected by a wire 7& with the coils of portedupon the frame of the field-magnet G and insulated therefrom. The post 0is also connected by a wire 0 with the fixed member Z of thecircuit-closer, and said wire 0 is part of the branch circuit, in whichis included the rotary armature D of the motor. A wire 0 connects themovable member Z of the circuitcloser with the commutator-brush n of themotor, and the said wire 0 also forms a part of the branch circuitwithin which the rotary armature of the motor is located. A wire 13connects the post 0 with the rod 1;.

The circuit of the lamp is as follows: Starting at the connection at theupper end of the rod 72 the current passes down through the rod 1" tothe brushes 7t through the wire It to the arc-forming magnet, and thencethrough the wire 70 to the lower and upper carbons, and down the rods 9and g and shaft d and rod 0 into the base 0, and from the base 0 throughthe wire Z to the field-magnet G,

thence to the post 0, and then by wire p to the rod 1 and to the line.

The passing of the current through the field-magnet G causes the same tomagnetically attract and move the supplemental armature Z in a directionto move the member Z of the branch circuit-closer, so as to open thebranch circuit, and during the operation of the lamp this switch orcircuit-closer is held normally open until the resistance due to theconsumption of the carbons and strengthening of the arc is such that thestrength of the field-magnet is reduced to such an extent that themember Z of the circuit-closer, which serves as a retractile spring forthe supplemental armature, will overcome the strength of thefield-magnet and will cause said armature Z to retract and close thebranch circuit. The rotary armature of the motor will then be caused torotate, and through the medium of the worm f and worm-gear e the shaft dwill be revolved and the disk b, carrying the lower carbon, willbe fedupwardly, while the upper carbon will be fed downwardly sim ultaneouslyat half the rate of speed at which the lower carbon is fed upwardly.Then the resistance is reduced at the are, which will occur when thecarbons approach each other, the strength of the field-magnet G willincrease to a sufficient extent to attract the armature t open thebranch circuit, and thus stop rotation of the armature, and consequentlythe feeding of the carbons. This condition exists until the resistanceis again increased, due to the consumption of the carbons andlengthening of the arc, when the operation will be repeated.

Upon the rods 2' and c" is mounted a reflector-disk 0', which is placedin the inverted position shown, and supported between nuts 8, fitted tothe threaded portions of the rods 2' and 2". The bottom of the disk r isarranged so as to come below the arc and to reflect the rays of lighttherefrom upwardly against a ceiling from which the lamp may besuspended, and the light is reflected downwardly from the ceiling anddiffused uniformly about a room or the like, so as to give the bestilluminating effects. The disk 1" is formed with a centrally-locatedopening r through the bottom thereof, which is lined with a bushing r ofasbestos or other suitable heat and electrical insulating material,through which the lower carbon projects to the upper side of the disk r.Openings 1" r are also provided, which permit of the passage freelytherethrough of the shaft 01 and post 0.

It will be seen that the field-magnet G not only serves its purpose asthe field-magnet of the motor, but also acts as a relay to control themovements of the supplemental armature Z movement of which to and fromthe field magnet opens and closes the circuitcloser.

The rotary armature of the motor is in multiple with the field-magnet,and the voltage it will receive will depend upon the length of thewinding .upon the field and upon the amount of current passing in thatwinding.

I claim- 1. In an electric-arc lamp, an actuator for the carbon-feedingmechanism consisting of a motor comprising a field-magnet in series withthe carbons having two pairs of poles, a rotary armature between thepoles of one pair, a normally open branch circuit therefor, acircuit-closer for said branch circuit, a supplemental armature foroperating said circuit-closer, located opposite the poles of the otherpair responsive to variations produced by the varying resistance of thearc, substantially as described.

2. In an electric-arc lamp, feeding mechanism for the carbons comprisinga feedingscrew for each carbon, one of which is made hollow andinternally screw-threaded to receive the other, means for turning saidhollow screw-shaft by hand, and an actuator c011- sisting of a motorcomprising a field-magnet, and a rotary armature, the latter beingoperatively connected with said hollow screwshaft, substantially asdescribed.

3. In an electric-arc lamp, the combination with actuating mechanism, offeeding mechanism for the carbons comprising a hollow shaft externallyand internally screw-threaded, the internal threads having one-half thepitch of the external threads, said shaft receiving upon it thelower-carbon support,and receiving within it a screw-threaded rod whichis connected with the upper-carbon support, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

CLARENCE C. STIRLING.

Witnesses:

CLAYTON P. CHAMBERLTN, FRANK B. SMITH.

